USB extender

Abstract

The present invention relates to a system and method for extending the distance between USB hosts and USB devices. Provided are USB 2.x compatible extenders capable of separating a USB device from a USB host by more than 30 meters while maintaining an at least approximately 480 Mb/sec data rate.

1 . A USB extender connectable to a USB host and to a USB device for extending the distance between the USB host and the USB device, the USB extender having the capacity to extend a D+ signal and a D− signal between a USB host and at least one USB device more than 30 meters wherein the data transfer rate of the D+ and D− signals between the USB host and USB device is at least approximately 480 Mb/sec and wherein the D+ signal and D− signal are skewed by less than 100 ps.  
   
   
       2 . The USB extender of  claim 1  wherein the USB extender is connectable to a non-USB communications channel and wherein the D+ and D− signals are transmitted over the non-USB communications channel.  
   
   
       3 . The USB extender of  claim 2  wherein the non-USB communications channel comprises at least one of: copper wire, optical fiber, and wireless.  
   
   
       4 . The USB extender of  claim 3  wherein the D+ signal is transmitted over one wire of a copper wire pair and the D− signal is transmitted over the other wire of the copper wire pair.  
   
   
       5 . The USB extender of  claim 3  wherein the D+ signal and D− signals are transmitted on separate optical fiber cables.  
   
   
       6 . The USB extender of  claim 3  wherein the D+ and D− signal are combined into a single-ended at least approximately 960 Mb/sec signal.  
   
   
       7 . The USB extender of  claim 6  wherein the single-ended at least approximately 960 Mb/sec signal is transmitted over a single optical fiber cable.  
   
   
       8 . The USB extender of  claim 1  wherein the USB extender is connectable to a USB host and to at least one USB device via USB communications channels.  
   
   
       9 . The USB extender of  claim 1  wherein the USB extender is configured to accept any USB device.  
   
   
       10 . The USB extender of  claim 1  wherein the USB extender is connectable to multiple USB devices.  
   
   
       11 . The USB extender of  claim 1  wherein the USB extender extends the distance between a USB host and a USB device without emulating either the USB host or the USB device.  
   
   
       12 . The USB extender of  claim 1  wherein the USB extender is a passive extender.  
   
   
       13 . A USB extender assembly, comprising: 
 the USB extender of  claim 1;     a non-USB communications channel;    at least one USB device; and    a USB host.    
   
   
       14 . The USB extender of  claim 13  wherein the USB extender comprises: 
 a host unit connectable to the USB host and the non-USB communications channel; and    a device unit connectable to the USB device and the non-USB communications channel.    
   
   
       15 . The USB extender of  claim 14  wherein the device unit further comprises a hub connectable to multiple USB devices.  
   
   
       16 . The USB extender of  claim 14  wherein the host unit and device each comprise: 
 a transmitter module having a transmitter for receiving USB data from the USB host or the USB device and transmitting the received USB data over a non-USB communications channel; and    a receiver module having a receiver for receiving data from the non-USB communications channel and transmitting the received USB data to the USB host or the USB device.    
   
   
       17 . The USB extender of  claim 16  wherein both the transmitter and receiver modules are communicably coupled and function in a master-slave relationship.  
   
   
       18 . The USB extender of  claim 17  wherein the receiver module is the master and the transmitter module is the slave.  
   
   
       19 . The USB extender of  claim 16  wherein the transmitter comprises at least one of a copper wire transmitter, a wireless transmitter, and a optical transmitter.  
   
   
       20 . The USB extender of  claim 16  wherein the transmitter module comprises: 
 a synchronizer for synchronizing the D+ and D− signals and decrease skew introduced between the extender and the USB host or USB device; and    a transmitter for each of the D+ and D− for transmitting the D+ and D− signals over the non-USB communications channel.    
   
   
       21 . The USB extender of  claim 16  wherein the receiver module comprises: 
 a receiver for each of the D+ and D− signals for receiving the D+ and D− signals transmitted over the non-USB communications channel; and    a synchronizer for synchronizing the D+ and D− signals and decrease skew introduced between the host unit and the device unit.    
   
   
       22 . The USB extender of  claim 16  wherein the transmitter module comprises a differential to single-ended converter, wherein the USB data received by the transmitter is first converted by the differential to single-ended converter and wherein the transmitter is a single-ended transmitter.  
   
   
       23 . The USB extender of  claim 16  wherein the receiver module comprises: a single-ended receiver for receiving converted single-ended USB data from the non-USB communications channel and a single-ended to differential converter.  
   
   
       24 . A method for extending the distance between a USB host and at least one USB device, the method comprising: 
 receiving at a device unit a D+ signal and a D− signal from at least one USB device via a USB communications channel, the D+ and D− signals being at least approximately 480 Mb/sec signals;    converting the D+ and D− signals to a single-ended at least approximately 960 Mb/sec signal;    transmitting the at least approximately 960 Mb/sec single-ended signal over a non-USB communications channel;    receiving at a host unit the at least approximately 960 Mb/sec single-ended signal via the non-USB communications channel;    converting the at least approximately 960 Mb/sec single-ended signal to at least approximately 480 Mb/sec D+ and D− signals; and    sending the at least approximately 480 Mb/sec D+ and D− signals to a USB host via a USB communications channel;    whereby the USB host and the at least one USB device are separated by more than 30 meters.    
   
   
       25 . The method of  claim 24  further comprising: 
 receiving at a host unit a D+ signal and a D− signal from a USB host via a USB communications channel, the D+ and D− signals being at least approximately 480 Mb/sec signals;    converting the D+ and D− signals to a single-ended at least approximately 960 Mb/sec signal;    transmitting the at least approximately 960 Mb/sec single-ended signal over a non-USB communications channel;    receiving at a device unit the at least approximately 960 Mb/sec single-ended signal via the non-USB communications channel;    converting the at least approximately 960 Mb/sec single-ended signal to at least approximately 480 Mb/sec D+ and D− signals; and    sending the at least approximately 480 Mb/sec D+ and D− signals to at least one USB device via a USB communications channel.    
   
   
       26 . A method for extending the distance between a USB host and at least one USB device, the method comprising: 
 receiving at a device unit a D+ signal and a D− signal from at least one USB device via a USB communications channel, the D+ and D− signals being at least approximately 480 Mb/sec signals;    transmitting the at least approximately 480 Mb/sec D+ and D− signals over a non-USB communications channel;    receiving at a host unit the at least approximately 480 Mb/sec D+ and D− signals via the non-USB communications channel;    reducing skew between D+ and D− signals resulting from transmission over the non-USB communications channel; and    sending the at least approximately 480 Mb/sec D+ and D− signals to a USB host via a USB communications channel;    whereby the USB host and the at least one USB device are separated by more than 30 meters.    
   
   
       27 . The method of  claim 26  further comprising: 
 receiving at a host unit a D+ signal and a D− signal from a USB host via a USB communications channel, the D+ and D− signals being at least approximately 480 Mb/sec signals;    transmitting the at least approximately 480 Mb/sec D+ and D− signals over a non-USB communications channel;    receiving at a device unit the at least approximately 480 Mb/sec D+ and D− signals via the non-USB communications channel;    reducing skew between D+ and D− signals resulting from transmission over the non-USB communications channel; and    sending the at least approximately 480 Mb/sec D+ and D− signals to at least one USB device via a USB communications channel.